Abstract

Abstract Plasmonic nanoarchitectures refer to the well‐defined groupings of elementary metallic nanoparticle building blocks. Such nanostructures have a plethora of technical applications in diagnostics, energy‐harvesting, and nanophotonic circuits, to name a few. Nevertheless, it remains challenging to construct plasmonic nanoarchitectures at will inexpensively. Bottom‐up self‐assembly is promising to overcome these limitations, but such methods often produce defects and low‐yields. For these purposes, DNA has emerged as a powerful nanomaterial beyond its genetic function in biology to either program or template synthesis of plasmonic nanostructures, or act as a ligand to mediate large‐area self‐assembly. In conjunction with top‐down lithography, DNA‐based strategies can afford excellent control over internal and overall structures of plasmonic nanoarchitectures. In this review, we outline the representative methodologies for building various well‐defined plasmonic nanoarchitectures and cover their recent exciting applications. WIREs Nanomed Nanobiotechnol 2012, 4:587–604. doi: 10.1002/wnan.1184 This article is categorized under: Diagnostic Tools > Diagnostic Nanodevices Diagnostic Tools > In Vitro Nanoparticle-Based Sensing Nanotechnology Approaches to Biology > Nanoscale Systems in Biology

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Applications of DNA‐based plasmonic nanostructures. (a) Colorimetric DNA detection method using DNA‐functionalized particles as probes and the complementary DNA strands as target molecules. (b) Plasmon ruler used in the detection of the hybridization of complementary DNA to the ssDNA linkers. After hybridization, the particles were pushed apart due to the more rigid nature of dsDNA than ssDNA, which resulted in a blue‐shift of ∼2.1 nm measured by monitoring the spectrum of single AuNPs dimer. (c) SERS‐active Au–Ag core–shell nanodumbbells assembled by DNA hybridization. In this nanostructure, a single Raman‐active Cy3 dye molecule is located in the gap of this heterodimer, followed by Ag shells deposition on the surface of the dimeric nanodumbbell. Left figure shows Raman spectra taken from Cy3‐modified oligonucleotides (red line) and Cy3‐free oligonucleotides (black line) in NaCl‐aggregated silver colloids.

(a) DNA‐functionalized AuNPs can be assembled into different crystallographic lattice structures programmed by the sequence of the DNA linkers. (b) Schematic of hexagonal superlattice of standing AuNRs with corresponding TEM images. (c) Scheme illustration of using 3D hollow DNA spacers in AuNP crystallization. TEM images of a bcc lattice (left) formed from AuNPs (20 nm) and DNA spacer (10 nm), and ‘Lattice X’ (right) structure formed from AuNPs (10 nm) and DNA spacer (20 nm). (d) Controllable switching of interparticle distances by using a reconfigurable DNA device (ld) that acts as an interparticle linkage. After addition of set DNA strands (s1, s2), ld structure can be reversibly transformed from a flexible C configuration to stem loop RS and linear RL morphologies.